A257445 Number of (n+2) X (6+2) 0..1 arrays with no 3 x 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 1 and no column sum 1.

90, 95, 104, 116, 134, 161, 200, 257, 341, 464, 644, 908, 1295, 1862, 2693, 3911, 5696, 8312, 12146, 17765, 26000, 38069, 55757, 81680, 119672, 175352, 256955, 376550, 551825, 808703, 1185176, 1736924, 2545550, 3730649, 5467496, 8012969, 11743541

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-3) - a(n-4) for n>5.

Empirical g.f.: x*(90 - 85*x + 4*x^2 - 87*x^3 + x^4) / ((1 - x)*(1 - x - x^3)). - Colin Barker, Dec 21 2018

Example

Some solutions for n=4:
..1..1..1..1..1..1..1..0....0..0..0..0..0..0..0..0....1..1..1..1..1..1..1..1
..1..1..1..1..1..1..1..0....0..1..1..0..1..1..0..1....1..1..1..1..1..1..1..1
..0..0..0..0..0..0..0..0....0..1..1..0..1..1..0..1....0..0..0..0..0..0..0..0
..1..1..1..1..1..1..1..0....0..1..1..0..1..1..0..1....1..1..1..1..1..1..1..1
..1..1..1..1..1..1..1..0....0..0..0..0..0..0..0..0....1..1..1..1..1..1..1..1
..0..0..0..0..0..0..0..0....0..1..1..0..1..1..0..1....0..0..0..0..0..0..0..0

Crossrefs

Column 6 of A257447.

Sequence in context: A271233 A050652 A025377 * A138692 A057455 A088470

Adjacent sequences: A257442 A257443 A257444 * A257446 A257447 A257448

Keyword

nonn

Author

R. H. Hardin, Apr 23 2015

Status

approved